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تسجيل مستخدم جديدMore bijections for Entringer and Arnold families
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The Euler number $E_n$ (resp. Entringer number $E_{n,k}$) enumerates the alternating (down-up) permutations of ${1,dots,n}$ (resp. starting with $k$). The Springer number $S_n$ (resp. Arnold number $S_{n,k}$) enumerates the type $B$ alternating permutations (resp. starting with $k$). In this paper, using bijections we first derive the counterparts in {em Andre permutations} and {em Simsun permutations} for the Entringer numbers $(E_{n,k})$, and then the counterparts in {em signed Andre permutations} and {em type $B$ increasing 1-2 trees} for the Arnold numbers $(S_{n,k})$.
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